In my previous U.S. Pat. Nos. 3,957,400 and 3,915,595, there is disclosed a downhole, hydraulically actuated pump assembly which can be circulated into and out of a borehole. In my copending patent application Ser. No. 001,093, filed Jan. 5, 1979, now abandoned, there is disclosed a packer nose assembly which can be used in conjunction with downhole apparatus such as exemplified by these two recited patents. The packer nose assembly includes a pair of spaced apart cup devices which are arranged in spaced relationship respective to one another so that the rubber elements of the cup sealingly engages the interior of the tubing string as the pump assembly is circulated downhole.
Circulation of power fluid downhole to a hydraulically actuated pump so that produced fluid, along with the spent power fluid, is forced up to the surface of the ground--requires a substantial amount of energy. In a free-type pump, it is absolutely essential that the production inlet be efficiently sealed to the seat formed in the lower shoe, and that the annulus formed between the upper end of the pump and the tubing string be absolutely sealed off, or otherwise power fluid is wasted.
Moreover, as the pump engine reciprocates the production pump, vibratory energy can cause harmonic motion to be induced into various different downhole pump components. This action can cause undesirable motion between the pump and the pump cavity.
The seal means on a packer nose assembly must sometime travel more than two miles through the interior of the tubing string and therefore the cups are subjected to considerable wear. Moreover, debris can become lodged outwardly of the rubber seal element of the seal cup, and this also promotes leakage across the pump annulus.
It would therefore be desirable to have a packer apparatus which augments the sealing action of the seal cup, and which furthermore positively anchors the entire pump device downhole in the borehole. It would be desirable if such an apparatus could be actuated by the same fluid pressure which powers the engine of the downhole pump. An apparatus which achieves these desirable results is the subject of the present invention.